Stabilization of furan



Patented Nov. 29, 1949 STABILIZATION OF FURAN Oliver W. Cass, NiagaraFalls, N. Y., assignor to E. I. du Pont de Nemours & Company,Wilmington, DeL, a corporation of Delaware No Drawing. Application April29, 1946, Serial No. 665,901

2 Claims.

This invention relates to the stabilization of heterocyclic organiccompounds and in particular to the stabilization of furan.

Furan, a compound which is useful in synthetic organic chemistry and inspecial cases as a solvent, is known to be unstable under ordinaryconditions of storage. Freshly purified furan is a colorless liquidwhich undergoes polymerization and acquires an undesirable color onstanding for relatively short periods of time even when protected fromexposure to light. This tendency to become colored and contaminated withpolymerization products obviously is undesirable since for most uses,the furan must therefore be purified and used immediately. Thus whenfuran is to be used at a distance from the point of production, time andlabor are required for an additional purification and also economiclosses are incurred since part of the product is always lost during thehandling and purification.

It is one of the objects of this invention to provide a novel method forthe stabilization of furan. Another object of the invention is toprevent polymerization and undesirable discoloration of furan duringshipment or storage. A further object is to provide a stabilized furancomposition. An additional specific object of the invention is toprovide a novel stabilizer for furan. These and other objects will beapparent from the ensuing description of the invention.

The above objects are attained in accordance with my invention byincorporating into furan hydroquinone.

I have discovered that when small amounts of hydroquinone are added tofuran polymerization and color formation are prevented. Furan which isstabilized with hydroquinone in accordance with my invention may bestored over relatively long periods of time without deterioration.

Various concentrations of hydroquinone may be utilized. In general,about 0.01 to 1.0% of hydroquinone based on the Weight of furan issatisfactory. and I prefer to utilize concentrations within this range.However, concentrations greater than 1% may be utilized although higherconcentrations usually have no advantage. Although less than 0.01%exerts some stabilizing action, I have found it desirable forconsistently good results to utilize more than 0.01%.

The following example is illustrative of my invention.

Example A sample of furan was distilled and the purified product dividedto provide several smaller samples. These samples were immediatelyplaced in plain glass bottles containing strips of iron and a space wasleft in each bottle between the stopper and the upper level of the furansample so that the furan Was continuously in contact with air.Hydroquinone in a concentration of 0.1% Was added to each sample and theclosed bottles containing the stabilized furan and iron were allowed tostand at room temperature in diifused light. At the end of 30 days, nocolor or polymer formation could be detected. Samples of furan placed inglass or iron containers Without any added stabilizer developed colorand polymer formation within a few hours.

Since polymer formation in furan is always accompanied by the appearanceof color the presence of polymerization products can be readily detectedby a determination of the color characteristics of the furan. This maybe accomplished simply by comparison of a given sample of furan with afreshly purified sample or with astandard.

The present invention provides a simple and economical method for thestabilization of furan so that the material may be stored for relativelylong periods or shipped lon distances without color formation orpolymerization in appreciable amounts. By the utilization of myinvention, it is unnecessary to redistill or further purify stabilizedfuran prior to use.

I claim:

1. The method of stabilizing furan which comprises incorporating therein0.01 to 1.0% of hydroquinone by Weight.

2. A new stable furan composition comprising furan having incorporatedtherein 0.01 to 1.0% by weight of hydroquinone.

OLIVER W. CASS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,143,941 Crawford Jan. 17, 19392,255,483 DiAlelio Sept. 9, 1941 FOREIGN PATENTS Number Country Date181,365 Great Britain 1 of 1923 OTHER REFERENCES Gilmans "OrganicChemistry, vol. 1, 2nd ed., 1943, pages 656 and 657.

